Each year, an estimated 1.7 million patients in the U.S. experience a hospital infection (CDC). Approximately 750,000 of these infections lead to severe sepsis, with over 200,000 patients dying [1]. As a result, $16 billion (40% of all intensive care unit expenditures) is spent each year managing patients with sepsis [1]. Sepsis is a potentially fatal condition in which the presence of an infection results in a whole-body inflammatory state, followed by multiple organ dysfunction. Delayed identification of sepsis, or a delay in initiation therapy after sepsis is recognized, remains a serious problem. Published studies have demonstrated that for every one hour delay in the administration of appropriate therapy there is an associated 7% rise in mortality [2]. While molecular techniques have shortened the gap between clinical observation and confirmation of sepsis, the microorganism must be present in the clinical sample-usually the blood-at a sufficient level for detection. Indeed, this is the major limitation, as bacterial levels are not always present in the blood sample. A potentially more sensitive and efficient method for detecting an infectious agent and its associated sepsis is by measurement of the patient's immune profile. Our work has focused on developing a rapid blood test that detects a Pre-symptomatic Sepsis-related Transcript (PreSepT) signature. PreSepT has the potential to detect acute bacterial infections before the onset of clinical symptoms (e.g., fever, increase heart rate, increased blood count.). Unlike existing diagnostics, PreSepT can also be used to improve patient care by measuring their response to therapeutic intervention. Ultimately, the goal is that PreSepT will provide physicians a longer window of opportunity to treat patients, personalize patient treatment for better care, and decrease sepsis and sepsis-related death rates. The objectives of the proposed studies are to: (1) optimize a rapid, focused blood RNA profiling assay; (2) prototype an integrated data capture and analysis software system; and (3) validate the diagnostic test in a retrospective pilot study using relevant patient samples. A non-invasive, blood diagnostic that detects bacterial infections and provides a pre-symptomatic diagnosis and prognosis for sepsis would provide profound medical advancement in decreasing sepsis cases associated with hospitalized patients. PUBLIC HEALTH RELEVANCE: Current diagnostic assays to diagnose and confirm sepsis are limited in sensitivity. This project aims to develop a novel blood test for the pre-symptomatic detection of sepsis that profiles a person's immune response. Success would provide physicians an earlier opportunity for patient treatment, resulting in a significant reduction in sepsis-related morbidity and mortality and its associated costs in the US, and globally.